Motor-control system.



nciisn, oF SCHENECTADY. New YORK, assienon To enit-@nat as narnia' amounts'.

FRA?

COMPANY, A CORPORTIGN F NEV YORK. y I. l nu l -i s' i Application led November 21, 1914. Ser2i1No. 873,392.

1'?, a7? ifi/ioni z'ztmzy/ concern:

lle it lniovvii thatl. FRANK SWW il eiizeii,4 of tue tinted States, residing,T at

Flcliene'ctadvcounty oi Schenectady. Stato ot Veiv York. li Jve invented certain new and useful linproieirfeiits iii ilotor-Qo'ntrol Systems. of which the'folloiviiigis a specification. .t l

This invention relates. to the control of electric motors andvlias for its object the provision of in'ipioved neans whereby an electric iiiotor may be started. and broughtup to sp'eedin a reliable, sate and efliciciit 'ianneix Bly invention relates more specifically to 'the control of electric motors by automatic or semi-automatic means. In the operation olf motor controllers of this general type, it common to have the operation ofthe controller;.under the control of the motor current soithat the cutting out ot resistance or otlieiestarting operation ivill be lstopped upon eacliqrise of .current until the current s to a predetermined value, and a safev current will not therefore be ettlt i'si'trequently desirable. however, thattlie limiting canient value should vary to suitoperating` conditions. This is partici.ilaii",lv't1ii'e of' control for electric railna-.ysuvhere ythe duty is frequently quite severe. tor instance, on rounding sharp curves -or fscending a heavy gra de. Under theseieoiiditions. the normal speed of startingrf would be too high andthe slipping point ot' the vWheel would be reached and Vwhile it desirable that the limiting' current should be in encess of that normally permitted so as to 'givevtlie necessary torque to the motors, it is also'desirable that-the controller should be operatedV more slowly under this high current condition instead of ,beingv stopped, as common practice. Inzotlier Words, when the conditions require alieavycui-rent the cvfiiitrollers will loe permitted tov operate more sloivly than when the current is light, but the operation of the controller should not be positively stopped. Likewise when the current is light, as in the.v case where ral' the normalvi'unning current eistsythat is,` when the'motoras-operated atI-full speed the 'MOTOR-CONTROL S ISTEM.

controller should be capable oit-".beingioper'# ated more rapidly. Whom oriiist'anee. the" controller is in full speed '.vpositio motors have reached running vspel l., any reason the operator should turnthe controller to the off posititin-toi"au instant and should immediately turn it on again, as frequently occurs iii pi*actiasetliel)peration of the controller hack tothe pointwvher`e- 'i I 6l) it had been should be as rapidas possible.l

One-ofthe objects of inv iveiitionis to provide a controller 'vvliiclrvvilloperate in the manner above descrip 'li' '(nel very eti-l ective nieans for prillduc y i i tarding effect is o v the use of air electromagnetic rotar-ding` `device which will 'halvefv'a greater retarding effect when Vthe current is heavy than when it is light The arrange@ nient is preferably such that al fl t three speeds of acceleration are peil. L d-#`'{ii'st,`- the maximum Speed 'when-tlieinotor current is at normal or below d. the accelera/f tion speed outing; orffliiiarstarting-.co-ndi# tions; and third.' t acceleration@ speed When the. load cond" inetliod of aoconipl, the use of current iielayyfiiiclr liaslftlii'ee- `positions for the three dinei-ent *values of ogerating current. each position producing a diiierent retarding effect upon the.V con! Vtroller. l Y.

Other oblliects and purposes of iiiy 'inv'e'ntion ivill appear in the course of the .fol-f lowing specification in wh'iclrl have shown in v invention embodied in concrete foi-infor purposesof illustration. 4.* l

desired-re'- u In the drawing illustrating' my inveifi'tioin` Figure 1 is ari-illustrative 'diagram of myv f invention applied toa tranicontrolsysteing Fig. 2 is ,a viewof the"controllerjpartly broken away to show the'detail's; *Fig-"3" shows a' detailof the reta-filing d evi'cegfand Figs. l and-5 shoiv7 connections tor'afinodi'f tied form: of '.iny invention. f l

.Referringto Fig. l it "will beseenf I have illustrated vmy invention iii connec-k tioii-*ivith a series parallel Ff'conti'ol' iorelec-i ti'ic vmotors of the -niultiplel unittyp'eg 'alf' though it will be' obvious lthat"myinventiony isin no sense limited to this 'particularitype i 1arton system of conti-ol.. In this diagram, A the motor, the contacts will not be operated. 65

and A .represent the armatures,=and F and F the lield's, respectively,j .oathe tractlon motors. These motors are controlled in the .well known manner by means of contactors (not shown) located in the box 1.0. A mas- .ter controller C controls thesecontactors in a manner well .understood in the art and I have shown it of the drurn'type for Athis purpose. Thismaster controller' isl such as to provide for automatic or semi-automatic operation, that is, when the operator moves 'the controller to a definite positionl the coiinections afremade automatically under the control of the motor currentso as to, bring the motor or motors up to the speed corresponding .to the position of themaster controller. i

lReferring' to Fig. 2, it will bel seen that the controller handle 11. is connected to the controller cylinderv 12 by a spring 13, so

that when the controller handle is turned, the spring will be placed under tension and the cylinder will follow the handle as fast as it ispermitted. The operator.may turn the controller handle to the position`representing full speed operation, but the cylinder which controls the circuits is under the control of the motor current, and cannotopera-te fast enough jto .caus'e damage to the motors.

out actually stopping'it, I 4provide an electromagnetic retarding device B which is in the nature of an electric motor, the armature magnetic field comprising a magnetic struc- 4ture 19 and a winding 20 for -magnetizing It is obvious that if the current the same. in the winding 20 is relativelyhighl the eX.- citation will be high, and therefore the controller will be retarded to a greaterrextent than if the exciting current were low.

In order to give predetermined values of' excitation, and hence predetermined rates of retardation, I have shown in Fig.- 1 a relay operated by the motor current to control a `theeontact 2 3, thereby short cireuiting' i the resistance R in addition Vtothe resisti' 12.0

resistance in series with the field Winding 20. The operating winding 21 of the relay is in the motor circuit and is provided lwith .two switch contacts 22 and 23'.which con- 'Such that at the normal running current of In order fto vretard the cylinder more or less dependent upon the current with-- severe operating conditions, as, for instance,4

in ascending, a grade or rounding a sharp curve, the current 1s suiiclent to raise the plunger ofthe relay still farther and close the contact 23. .This will short lcircuitl the resistance R and increasethe eld excitationfof the retarding device and the operation of' the controller.

As thus constructed and arranged,'.the

operation of my device isl as follows: -To

slow down '.start the car or train,-theoperator turns the.

handle '11 to the position corresponding to the speed desired. Hemay turnto the seriesparallel position in the typeof control which I have illustrated, orfhemay turnitto the full parallel positionrepresenting full speed.

In either case, 'the cylinderwhich makes the circuit connections will be operatedslowly owing to the'reta'rdation of the re- Vta'rding device. Assuming that the operatorl is starting'l on an ordinary stretch of straight level track, the starting current will be 'snflicient to cause therelay to-operate to close theveontact 22. Thiswillshort'circuit the.

resistance R and increase the field excitation of the retarding device. The retarding eiiect will be such as to permit, the cylinder to operate at ythe properspeed under existing load conditions. The icylinder willcontinue to rotate, making the .necessary conynections, until it reaches the position predetermined by the operator. train-has been brought upto the'speedgfre- 'quired by the position Aof" the operating handle, the operator should throw' off, his controller, as for -instance,' where a danger .signal is flashed for an inst-ant and then .,clea'red, the relay will drop and will not close at the normal running "current,.so that' .the operator will be able to move'the con- I f, after the icowhichit was moved withoutbeing retarded,

mitted by theretarding'device. If the train should be started on a grade or curve, or

. or at. least'with. the maximum speed perunder other' severe'load-conditions, the cur- --rentin the relay will be sufficient to close ance R, and further increasing. the excitation ofthe retarding device. Un'der these.

'conditions the cylinder of the controllerfwill be moved to make the'proper connections,

load condi-tions without endangering the 'motors or slipping the wheels,A

Laconic In Figs. 4c and 5 l have shown the retarding device arranged 1n a somewhat different ymanner.. ln this case the Winding of the re-` vices, however, has the advantage of giving and definite retardation values, which in most cases would "ce an advantage over thegradually varying lretardation value which depends upon the gradually varying current.

lt will he seen that l have-disclosed a motor controller of a simple form in Which while the motor starting is doneunder the control of the motor current the operator is not ui'iduly hampered in the control, but enabled 'to n'ieet the severe load conditions as they arise without danger.

describen my invention as predetermined lllliile l have `eudiodied in concrete form and as operating in a specific manner .tor purposes of illustration, it should he understood that I do not limit my invention theretoj since various modifications thereof will suggest themselves to those skilled in the art uithout d j irting from the spiriti ot my invention. the scope ot which is set forth in the annexed claims.

lllhat l claim as new and desire 'to secure by Letters llatent or"A the United States, is:

l. i co olA system for electric motors comprising "s, under the control oi" or current 'tor limiting the ed oi" operation the controller and uuans for decreasing said retarding etl'ect when the controller is moving toward t'ullv running position after it has been moved to the oil? piisition for an instant.

control system tor electric motors comprising a controller, means for causing said controller to advance automatically to start the motor. an electro-magnetic retarding` device tor said controller. and a relay operated at predetermined valuesol:l motor current to produce corresponding changes in the retarding effect of said device. y

3. A control system for electric motors comprising a controller', means tor causing said controller to advance auton'iatically to start the motor. a retail-ding device 'for said controller, and a relay moved by the motor current to predetermined positions depending` upon the. value of the operating current to produce changes in the retarding eilect ol3 said device.

4. A control system for electric motors comprising a controller, means for causing Sad Controller to advance automatically to start the motor', and retarding means under the control of the motor current orlimiting the speed of operation of said controller said means normally permitting maximum speed ot operation and being unaliected by currents below the normal running current of the motor.

5. A control system for electric motors comprisinga controllera means for causing said controller to advance automatically to start the motorj an electromagnetic retarding device for said controller, and a relay operated by the motor current to `etlect changes in the retarding effect of said de-A vice', said relay having an ofi position which it assumes whenl the currentis at or beloiv normal runnin-g current and tivo operative positions which it assumes at higher current values to producecorresponding changes in the retarding eliect of said device.

(i. A control system for electric motors comprising a` controller, means for causing saidvcontroller to advance automatically to start the motor, an electromagnetic retardingl device for said controller having a variable field excitation which determines the retarding effect, and a. relay ope 'ated by the motor current 'for varying the Field excitation.

T. A control system tor electric motors comprising a controller, means for causingy said controller to advance automatically to start the motor, an electromagnetic retarding device Jfor said controller having a vrinding for producing lield excitation,l a resistance in circuit with said Winding to vary the excitation and produce' different retarding etlccts. and a relay operated by the motor current to control the resistance.

8. A control system -tor electric motors comprising a controller, means tor causing said controller to advance automatically to start the motor, an electromagnetic retarding device for said controller` and means for producing changes iu the retarding effect comprising a relay operated by the motor current having an ott1 position which it aslsumes when the operating current is at or below the normal running current in which position the retarding cliect is a minimum and `two operative positionsv which it assumes at higher current -values to elfect corresponding changes in the rctarding device.

S). A control system for electric motors comprising a controller, means for causing;r said controller' to advance. automatically to start the motor. an electromagnetic retarding device for said controller having a Winding for producing field excitation. an armature driven by the controller movable in said lield. a resistance in the circuit of said Winding, a relay operated by the motor Acurrent to vary the'resistance of said relay in the o position which it assumes when the oper'- ating currentis at o1' below normal running current in which position the field excitation is a minimum and two operative positions Which it assumes at higher current values in which the field excitation is progressively increased.

In Witness whereof, I have hereunto set my hand this 20th day of November 1914. FRANKE. CASE. Witnesses:

BENJAMIN B. HULL, HELEN Osroiz'n. 

